Pump or motor for high hydraulic pressures



E. ORSHANSKY, JR

April 17, 1956 PUMP OR MOTOR FOR HIGH HYDRAULIC PRESSURES Filed June 20,1952 3 Sheets-Sheet 1 n .E :E:

April 17, 1956 E. ORSHANSKY, .JR

PUMP OR MOTOR FOR HIGH HYDRAULIC PRESSURES Filed June 20, 1952 3Sheets-Sheet 2 nm. z m w n A w. H 0. 0 S m 'Wg /E l. 6 0 9 l. W

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BY f

Trae/VE Y.

April 17, `1956 E. oRsHANsKY, JR 2,741,993

PUMP OR MOTOR FOR HIGH HYDRAULIC PRESSURES Filed June 20, 1952 3Sheets-Sheet 3 United States Patent O PUMP on MOTOR Fon HIGH HYDRAULICPREssUREs This invention relates to hydraulic apparatus capable offunctioning either as a pump or as a hydraulic motor. More particularly,the invention relates to a mechanism of this character in which aplurality of cylinders and pistons is utilized, operating in cyclicsequence as the rotor of the mechanism moves angularly.

Such mechanisms, in which an eccentric is utilized for obtaining thereciprocating action, are, in general, well known. However, when highfluid pressures are attained or utilized, intolerable leakage of the uidis encountered, and a corresponding reduction in eliiciency results.When utilized as a pump, these leakage effects render attainment of highpressures much more difficult. One manner in which the leak losses maybe reduced is by the aid of tight its between moving parts; but, in suchan event, the power loss for either pump or motor operation makes itincapable of commercial exploitation.

Itis one of the objects of this invention to make it possible to operatea mechanism of this character without intolerable leakage, and at highpressures.

In order to accomplish this result, the fluid pressures existing in themechanism are used to ensure the maintenance of close clearances betweenthe relatively moving surfaces; and, furthermore, any unbalanced forcesdue to asymmetrical iluid pressures are ineffective to cause separationof such closely contacting relatively moving surfaces.

This invention possesses many other advantages, and has other objectswhichmay be made more clearly apparent from a consideration of oneembodiment of the invention. Forthis purpose, there is shown a form inthe drawings accompanying and forming part of the present specification.The form will now be described in detail, illustrating the generalprinciples of the invention; but it is to be understood that thisdetailed description is not to be taken in a limiting sense, sinceythescope of this inventionis best defined by the appended claims.

Referring to the drawings:

Figure l is a vertical sectional view of an apparatus incorporating theinvention;

Fig. 2 is a sectional view, taken along a plane corresponding to line 22of Fig. l; f

Fig. 3 is a sectional view, taken along a plane corresponding to line 33 of Fig. 1;

Fig. 4 is a sectional view, taken along a plane corresponding to line4-4 of Fig. l;

Fig. 5 is a sectional view, taken along a plane corresponding to line5-5 of Fig. 1;

Fig. 6 is a pictorial view of the pressure balancing devices utilized inthe construction shown in Fig. 1;

Fig. 7 is an exploded view of one of the pistons cooperating with thecylinder block utilized in the invention; and

Figs. 8 and 9 are fragmentary sectional views, taken along planescorresponding,` respectively; to lines 8-8 and 9--9 of Fig. 2. f

The operation of the structure, in this instance, is de- Nce scribed forhydraulic pumping, although, as heretofore stated, it may be used justas well as a hydraulic motor.

The operating parts of the pump are enclosed in a casing or housingformed of a casing member 1 (Figs. 1 and 2) and having a complementarycasing member 2. A cover member 3 is also provided in which an inlet orintake port 4 and an outlet port 5 are formed.

The casing member 2 has a ange 6 telescoping within a correspondingopening in the casing member 1, and a sealing or O-ring 7 is disposed inan appropriate groove in the flange 6. The two casing members 1 and 2are appropriately fastened together, as by the aid of bolts or studs. 4

Similarly, the cover 3 has a ilange 8 telescoped within a cylindricalopening in casing member 2. An O-ring 9 extends in a groove disposedaround the ange 8, and serves to seal the casing. The cover member3 maybe appropriately fastened to the casing member 2 to provide a closed andsealed casing structure.

' The moving parts of the pump structure include a cylinder block 10rotatable about the main axis 11 of the apparatus. This axis extendstransversely of casing structure 1-2-3.

The cylinder block 1l), in this instance, is shown as provided withradially extending equiangularly spaced cylinder spaces 12 (Figs. lV and2), there being nine in the present instance. Each of the cylinderspaces 12 is provided atits inner end with a port 13 extendingcompletely through the cylinder block 10. Each of these ports 13 actsalternately as an inlet port and as an Outlet port during the course ofangular movement of the cylinder block 10 about axis 11. i Extendingradially outwardly from the Outer periphery of the cylinder block 10 isan interrupted flange 14 integral with the block,(see, also, Fig. 8).The arcuate edges 15, adjacent portions of the ange 14, serve asadditional guides for the reciprocating pistons 16 movable within thecylinder spaces 12.

The pistons are reciprocated by the rotation of the block 10.V Thisreciprocation is effected by the provision of a ring 17 mounted withinthe casing member 1 (Figs. l

and 2).` This ring 17 is pivoted upon a pin 1S for adjusti ing theeccentricity of its axis 19 with respect to the axis of rotation 11.`This pin 18 is appropriately fitted within the casing members 1 and 2.

Each of the pistons is provided with a contacting shoe 20 (see,particularly, Fig. 7). The outer surface of each of these shoes is incontact with the cylindrical interior surface 21 of ring 17. Ears 22extend radially inwardly from each shoe 20 to be pivotally joined to theat end 23 of the corresponding piston 16. This pivotal connection iseffected by the aid of a pin 24.

As the block 10 is rotated within the eccentric ring 17, the pistons 16operate to provide a stroke corresponding to the eccentricity betweenthe axes 11 and 19. In order to make this 1 stroke adjustable, anadjusting mechanism is providedjby the aid of which the angular positionof the eccentric ring 17 may be adjusted about 'the axis of its pivotpin -18. l

For this purpose, a longitudinally adjustable bar 25 extends across thetop of the `casing member 1. This bar 25 is provided with a transversepivot pin 26 to opposite ends ofwhich are attached a pair of blocks.These blocks are accommodated within pairs of ears 2S formed on oppositesides of the ring 17 Accordingly, movement ofA the bar 25Y toward theright, as viewed in Fig. 2, would serve to reduce the eccentricitybetween the axes 11 vand 19.- Similarly, movement of the bar 25 towardthe left would serve to increase the eccentricity.

Any appropriate-mechanism may be provided for the adjustment of the bar25. v For example, the bar 25 may be provided with cylindrical ends 29and 30 slidable in a housing 31, and adjusted by hydraulic pressure.This housing 31 is maintained in the casing 1 by the aid of the enlargedthreaded end 32 threaded into an appropriate aperture in the right-handwall of .casing 1. At its left-hand end the housing 31 is provided withan O-ring 33 accommodated in a groove formed in the `end ange of thehousing. The left-hand end of the housing is spaced from the right-.handend of a threaded member 34 for the accommodation of a sealing ring 35.This member 34 is threaded into the left-hand wall of the housing 1, andis provided with an O-ring 36 for eiecting an appropriate seal.

The cylindrical portion 29 is limited in its movement to the left by theright-hand surface of a stud 38. This stud 38 may be adjustably threadedinto the threaded aperture in 4the member 34 for adjustment -of theextent of travel of the bar 25 toward the left. This stud may be kept inadjusted position by the aid of a lock nut 39. An appropriate leakagedrain device 40 is disposed in the casing member 1 and communicates withthe interior of the casing.

In order to rotate the block about its axis 11, it is clamped between apair of rotatably mounted sleeve members. Thus, as viewed in Figs. l and4, a sleeve member 41 is provided, and which has radial extensions 42.These radial extensions provide an interrupted cylindrical surface 43which telescopes over the periphery of the block 10. The right-handsurfaces of these projections 42 contact the left-hand surface ofinterrupted flange 1'4. The

member 41 is generally cylindrical and provides a hub at its left-handend to serve as a support for the inner race 44 of a ball bearingstructure 45. The outer race 46 is accommodated within the cylindricalange 47 formed in the casing member 2.

Similarly, a sleeve member 48 (Figs. l and 3) is provided with radialextensions 49 facing the extensions 42 and aligned therewith. Thissleeve is provided with one or more apertures 74 (Fig. l) to permit anyof the' uid that may leak from the pump to enter into the casingmember 1. Radial extensions 49 provide an interrupted cylindricalsurface 50 telescoping over the right-'hand portion of the cylinderblock 10. The left-hand faces of the projections 49 contact theright-handv surface of the flange 14.

There are as many projections 42 and 49 as there are cylindrical spaces12, and they are located intermediate these cylinder spaces (Fig. 2).Through bolts 51 (see particularly Fig. 1) serve to hold the `sleevemembers 41 and 48 firmly in assembled relation with the 'block 10. Thesebolts pass through the aligned projections 42 and 49.

The sleeve member 48 has a reduced cylindricalportion 52 upon which ismounted the inner race 53 of the ball bearing structure 54. The outerrace 55 is accommodated within the hollow extension 56 of the casingmember 1. Extending to the Vright of the portion 52 is an integrallyattached hollow splined member 57 adapted to accommodate the splined endon a shaft 'for the rotation of the cylinder block 10.

In order to close the casing structure, a cover plate 58 is providedsurrounding the member 57 and'held in place as by a split spring 59.This plate 58 contacts the right hand surface of the ring 60, in whichouter race 55 Vis accommodated. A conventional sealing ring 64 iscarried by the plate 58 for cooperation with the exterior periphery ofthe splined member 57. The ring 60 of the ball bean ing structure has aleft-hand surfacecontacting lthe shoulder 61 in the casing member 1.Accordingly, the 'spring ring 59 serves to maintain the bearingstructure Aand the sleeve member 48 in appropriate axial kposition withrcspect to the casing 1.

- In yorder to ensure that the -shoes will be maintained against theinterior surface 21 ofthe ring 17 `without angular displacement'aboutpin 24, use is lmade of a .pair of guide rings 62 and 63. These aredisposed on each side of the ange 14, and are in contact with theinterior surface of the shoe 20. Furthermore, each of the shoes 20 isprovided with the side anges 65 for maintaining these rings 62 and 63against axial movement and for conning the rings against the ears 22.These rings are wide enough (Fig. l) to overlap the ends of the pins 24,thereby maintaining these pins against removal.

The cover member 3 is provided with an inwardly projecting cylindricalmember 66 (Figs. l and 4) that provides a smooth plane surface 67 towhich the left-hand surface of cylinder block 10 is opposed. Extendinginto this face is an arcuate outlet port 68 in communication with theport 5, as by the aid of a drilled aperture 110. A similar port 69,below the axis 11, is provided communicating with the inlet port 4 (seeparticularly Fig. 4).

These ports 68 and 69 are kidney-shaped, and each of them extends for anangle somewhat less than 180 around the .axis i1. They are adapted tocommunicate in succession with groups of cylinder ports 13 as thecylinder block 10 is rotated.

Thus, in the position of Fig. 2, those ports 13 above the horizontalline 70 are in communication with the outlet port 68; and those ports 13which are below the horizontal line 70 Lare in communication with theinlet port 69. As viewed in Fig. 2, therefore, as the block 10 rotatesin a clockwise direction, the pistons 16 above line 70, operating in thecylinders 12, are urged inwardly to a maximum inward position,illustrated at the righthand side of the block 10. Similarly, thepistons 16 in the lower portion of the block 10 gradually move outwardlyfor receiving a charge of liquid through the inlet port'69.

ln order to maintain a definite clearance for the block 10, a spacersleeve 7l is provided. This spacer sleeve extends through the block 10,and is doweled to the cy1indrical projection 66 `of cover member 3. Astationary wall-forming member 72 (Fig. 6) that has a left-hand face 73opposed .to the block 10 serves to conne this block against substantialaxial movement. This face is held in spaced-apart relation with respectto the wall 67 by the aid of the spacer sleeve 71. This member 72 may bedoweled to the spacer sleeve 71, as indicated in Fig. l. It is formedintegrally with a cylindrical extension 101 which is made eccentric withrespect to member 72 (Fig. 6).

The spacer 71 is made very slightly greater in length than the axialdepth of the block 10. Accordingly, the clearance between the block 10and surfaces 67 and 73 may be of the order of one-half of one-thousandthof an inch. In a typical construction, before there is any strain due topressures, the clearance between lthe block 10 and these walls 67 and 73is .0004 inch.

Without exceptional precautions, the outlet pressures, which may be ofthe order of several thousand pounds per square inch, would exert forcestending to urge the walls 67 and 73 apart. These forces are exelted viathe cylinder ports 13 located over the horizontal line '70 (Fig. l). Theresultant or combination of all these forces has a center ofgravitysubstantially above the line 70. Accordingly, this resultant force tendsto distort or cock the spacer '71, with consequent resultantmisalignmcnt of the parts and increased leakage.

In order substantially to balance the pressure affecting the spacer 71,a pressure space is kformed between the member 72 and-a supplementalpressure balancing mem- 'Der 75 (Figs. l and 6). For this purpose, thismember 75 has a surface 76 (Fig. 6) opposed to the rear surface 77 ofthe :member 72. The surfaces 7-6 and 77 are crescent-shaped due totheeccentricity of the outer periphery of the member 101 with respect tothe axis 11. Sealing O-rings 78 and 79 extend in grooves in the members72 and 1'01, and serve Vto Asealrespectively against the flange 80 ofmember75 and the cylindrical surface 81 cooperating with the right-handportion 101 of member 72. As indicated most clearly in Fig. l, the spaceformed annees between members 72 and 75 is quite confined, and is inconstant communication with the outlet port 68, via` the cylinder ports13 above line 70, and port 82` (see, also, Figs. 3 and 6). This portextends through the member 72 from a shallow recess 83 extendingsubstantially 180 around the axis 11, and located in the left-hand faceof member 72. Accordingly, the port 82 in this manner is incommunication with substantially all of the cylinder ports 13 thatextend above thehorizontal line 70; and the space between members 72 and75 is subjected to a hydraulic pressure corresponding to the highpressure side of the mechanism. The pressure acting on opposite sides ofmember 72 is thereby substantially balanced.

The exertion of pressure upon the surface 76 of member 75 tends to cockthis member about the axis 11. In order to ensure that this cocking canbe effected without in any way interfering with the proper alignment ofthe Walls 67 and 73, there is clearance between the flange 80 and theouter periphery of member 72, as well as between the cylindrical surface81 of member '75 and the extension 101 of member 72.

The spacer 71, however, is quite rigidly held in place by the aid of asupplemental sleeve member 84. This sleeve member extends through thespacer 71, and is held in place by the collar 85 formed integrally witha central post 86. This collar 85 engages the inwardly directed flange90, carried by the left-hand end of the sleeve 84. This ange urges thesleeve 84 toward the right-hand surface 67 of the boss 66. For thispurpose, the left-hand end 87 of the post 86 is threaded to engage in anappropriate threaded aperture in the boss 66.

The right-hand end of the sleeve 84 is provided with a ange 88. Theleft-hand surface of this flange 88 contacts the narrow annular boss 89(Fig. 6) extending around the through bore of the member 72. The ange 88urges the spacer 71 and member 72 tightly against the surface 67 Theflange 90 has a slight lclearance with respect to this surface to permita force to be exerted `by flange 88 upon the right-hand side of member72.

The post 86 carries a collar or flange 91 against which the right-handsurface of member 75 abuts. AAn enlarged portion 92 of the post 86extends toward the right of this `flange 91, and is mounted by the aidof a ball bearing structure 93 within the member 48.

The extension 92 serves as a rigid end support for the post 86 to resistiexure thereof. However, flexure of the member 75 is permitted, sinceclearances are provided between the member 75 and the cooperatingsurfaces of member 72 and sleeve 84.

The compensating pressure areas are indicated in general in Fig. 5. Thearea on the left-hand surface of member 72, as viewed in Fig. 1, whichis subjected to outlet -pressure, may be represented in Fig. by thesemicircular annulus above line 70, and between the circles 94and 95.The circle 94 corresponds `to the outer periphery of member 72, and thecircle 95 corresponds to the outer periphery of the spacer 71.

An opposing pressure on the right-hand surface of ,member 72, as viewedin Fig. l, is that corresponding to the crescent-shaped area between thecircle 94 and the circle 96. The latter circle 96 corresponds to theperiphery of the extension 101. The centers of gravity of these areasare substantially coincident. Furthermore, the areas lare substantiallythe same. Accordingly, there is substantially complete balance ofpressures on opposite sides of the member '72. A balancing of stressesacting upon the spacer 71 is thus substantially accurately effected.

The inventor claims: f l. In a hydraulic mechanism: a block; a memberhaving relative movement with respect to the block for utilization orcreation of hydraulic pressure; means for providing said movement; meansforming walls on opposite sides of the block; a spacer between saidwalls for `maintaining a running clearance for the block; one of saidlwalls having inlet and outlet passages; and means forming,

with one of the walls, a space on that side of the said wall opposite tothe side that faces the block, and in communication with one of thepassages, the surface of said side that forms said space presenting anarea of pressure for substantially balancing thev pressure on the otherside of said one of the walls.

2. In a hydraulic mechanism: a block; a member having relative movementwith respect to the block for utilization or creation of hydraulicpressure; means for providing said movement; means forming walls onopposite sides of the block; a spacer between said walls for maintaininga running clearance for the block; one of said walls having inlet andoutlet passages; means forming, with one of the walls, a space on thatside of the said wall opposite to the side that faces the block, and incommunication with one of the passages, the surface of said side thatforms said space presenting an area of pressure for substantiallybalancing the pressure on the other side of said one of the walls; andmeans for so mounting said spaceforming means as to permit deectionthereof independently of the cooperating wall forming means.

3. In a hydraulic mechanism: a block; a member having relative movementwith respect to the block for utilization or creation of hydraulicpressure; means for providing said movement; means forming walls onopposite sides of the block; a spacer between said walls for maintaininga running clearance for the block; one of said Walls having inlet andoutlet passages; means forming, with the other of the walls, a space onthat side of the said wall opposite to the side that faces the block,and in communication with one of the passages, the surface of said sidethat forms said space presenting an area of pressure for substantiallybalancing the pressure on the other side of said other wall; means forso mountingsaid space forming means as to permit deflection thereofindependently of the cooperating wall forming means; an abutment for thespace forming means; and means fastening said abutment to only the saidone of the walls.

4. In a device of the character described: means forming a pair ofspaced walls; a cylinder block between the walls; one or more pistonscooperating with cylinder spaces in the block; a spacer between thewalls for main` taining a running clearance for the block; said blockhaving cylinder ports; means providing relative angular movement betweenthe walls and the block about an axis for producing reciprocation of thepistons; one of said walls having a high pressure passage for fluidcommunicating with some of the cylinder ports; and means forming, withthe other wall, a pressure space on that side of the said other wallopposite to the side that faces the block, and in communication withsaid passage, the surface of said side that forms said space presentingan area of pressure for substantially balancing the pressure on theopposite sides of said other wall. l

5. In a device of the character described: means forming a pair ofspacedk parallel walls; a cylinder block between the walls; one or morepistons cooperating with cylinder spaces in the block; a spacer betweenthe walls for maintaining a running clearance for the block; said` blockhaving cylinder ports; means providing relative angular movement betweenthe walls and the block about an axis for producing `reciprocation ofthe pistons; one of said Walls having a high pressure passage for fluidcommunicating with some of the cylinder ports; and

ymeans forming, with the other wall, a pressure space on that side ofthe said other wall opposite to the side that faces the block, and incommunication with said passage, the surface of said side that formssaid space presenting an area of pressure substantially equal to thearea exposed on the other side of the other wall, to the high pressure.

6. In a device of the character described: means forming a pair ofspaced parallel walls; a cylinder blockl between the Walls; one or morepistons cooperating with cylinder spaces in the block; a spacer betweenthe walls for maintaining a running' clearance for the block; said blockhaving cylinder ports; means providing relative angular movement betweenthe walls and the block about an axis for lproducing reciprocation ofthe pistons; one of said walls having a high pressure passage for fluidcommunicating with some of the cylinder ports; means utilizing the iiuidpressure existing in said passage for substantially balancing the uidpressure on opposite sides of the other wall; and means so mounting saidspace forming means as to permit deflection thereof, independently :ofthe wall forming means.

7. In a device of the character described: means forming a pair ofspaced parallel walls; a cylinder block between the walls; one vor morepistons cooperating with cylinder spaces in the block; a spacer betweenthe walls for maintaining a running clearance for the block; said blockhaving cylinder ports; means providing relative angular 'movementbetween the walls and the block about an axis for producingreciprocation of the pistons; one of said walls having a high pressurepassage for fluid communicating with some of the cylinder ports; meansutilizing the uid pressure existing in 'said passage for substantiallybalancing the fluid pressure on opposite sides of the other wall; meansso mounting said space forming means as to permit deilection thereof,independently of the wall forming means; an abutment for the spaceforming means; and means fastening said abutment only to the one of saidwalls.

8. In a device of the character described: means forming a pair ofspaced parallel walls; a spacer between the walls; a rotary cylinderblock having an axis of rotation passing through the spacer and providedwith a plurality of cylinders; said block having running clearancebetween the walls; each of said cylinders having a port; pistons in thecylinders; means for causing the pistons to reciprocate as the block isrotated; one of the walls .having ,a high fluid pressure passagecommunicating cyclically with a portion of all of the cylinder ports asthe block is' rotated; and means forming with the other of said walls, aspace on that side said other wall, opposite to the side that faces thespacer, and in communication with said passage via said ports, thesurface .of said side that forms said space presenting an arca ofpressure for substantially balancing the pressure on the opposite sidesof said other wall.

9. In a device of the character described: means forming a pair ofspaced parallel walls; a spacer between the walls; a rotary cylinderblock having an axis of rotation passing through the spacer and providedwith a plurality of cylinders; said block having running clearancebetween the walls; each of said cylinders having a port; pistons in thecylinders; means for causing the pistons to reciprocate as the block isrotated; one of the walls having a high fluid pressure passagecommunicating cyclically with a portion of all of the cylinder ports asthe block is rotated; means forming with the other of said walls, aspace on that side of said other wall, opposite to the side that facesthe spacer, and in communication with said passage via said ports, thesurface of said side that forms said space presenting an area ofpressure for substantially balancing the pressure on the spacer; andmeans for mounting said space forming means in a manner to permitdeflection thereof independently of the cooperating wall forming means.

l0. In a device of the character described: means forming a pair ofspaced parallel walls; a spacer between the walls; a rotary cylinderblock having an axis of rotation passing through the spacer and providedwith a plurality of cylinders; said block having running clearancebetween the walls; each of said cylinders having a port; pistons in thecylinders; means for causing the pistons to reciprocate as the block isrotated; one of the walls having a high fluid pressure passagecommunicating cyclically with a portion of all of the cylinder ports asthe block is rotated; means forming with the other of said walls, a

space on that side of said other wall, opposite to the side that facesthe spacer, and in communication with said passage via said ports, thesurface of said side that forms said space presenting an area ofpressure for substantially balancing the pressure on the spacer; meansfor mounting said space forming .means in a manner to permit deectionthereof independently of the cooperating wall forming means; an abutmentfor the other side of said other walls; and means passing through thespacer for fastening said abutment to the said one of the Walls.

ll. In a device of the character described: means forming a pair ofspaced parallel Walls; a spacer between the walls; a rotary cylinderblock having an axis of rotation passing through the spacer and providedwith a plurality of cylinders extending radially of the axis; said blockhaving running clearance between the walls; each of said cylindershaving a port; pistons in the cylinders; means for causing the pistonsto reciprocate as the block is rotated; one of the walls having highiluid pressure passage communicating cyclically with substantially halfof the cylinder ports as the block is rotated; means forming anotherpassage communicating with the remainder of the ports; and meansforming, with the other of said walls, a pressure space with the otherwall and in communication with the high pressure passage via thecylinder ports, the surface of said other wall that defines said spacepresenting an area balancing the pressure on the spacer.

l2. In a device of the character described: means forming a pair ofspaced parallel walls; a spacer between the walls; a rotary cylinderblock having an axis of rotation lpassing through the spacer andprovided with a plurality of cylinders extending radially of the axis;said block having running clearance between the walls; each of saidcylinders having a port; pistons in the cylinders; means for causing thepistons to reciprocate as the block is rotated; one of the walls havinghigh fluid pressure passage communicating cyclically with substantiallyhalf of the cylinder ports as the block is rotated; means forminganother passage communicating with the remainder of the ports; meansforming, with the other of said walls, a pressure space with the otherwall and in communication with the high pressure passage via thecylinder ports, the surface of said other wall that defines said spacepresenting an area balancing the pressure on the spacer; and means formounting said space forming means in a manner to permit deflectionthereof independently of the cooperating wall forming means.

13. l'n a device of the character described: means forming a pair ofspaced parallel walls; a spacer between the walls; a rotary cylinderblock having an axis of rotation passing through the spacer and providedwith a plurality of cylinders extending radially of the axis; said blockhaving running clearance between the walls; each of said cylindershaving a port; pistons in the cylinders; means for causing the pistonsto reciprocate as the block is rotated; one of the walls having high uidpressure passage communicating cyclically with substantially half of thecylinder ports as the block is rotated; means forming another passagecommunicating with the remainder of the ports; means forming, with theother of said walls, a pressure space with the other wall and incommunication with the high pressure passage via the cylinder ports, thesurface of said other wall that deiines said space presenting an areabalancing the pressure on the spacer; means for mounting said spaceforming means in a manner to permit deflection thereof independently ofthe cooperating wall forming means; an abutment for that side oftheother wall which defines said space; and means passing thro-ugh thespacer for fastening said abutment to the said one of the Walls.

14. in a device of the character described: a rotary cylinder blockmember having an axis of rotation, and provided with a plurality ofcylinder bores opening in 9 the outer periphery of the block member;each of said bores having a port that opens on a side surface of theblock member; pistons in the cylinders; means for causing the pistons toreciprocate as the block member is rotated; a non-rotary wall memberhaving a surface adjacent one side surface of the block member, saidadjacent surfaces being subjected to outlet pressure; a spacer structureassociated with one of the members so as to provide a running clearancein an axial direction for the said one of the members; a casing for themembers and providing inlet and outlet openings adapted to communicatein succession with a group of cylinder ports;

10 and means utilizing outlet pressure for balancing the force due topressure existing on one of the said adjacent surfaces of one of themembers.

References Cited inthe le of this patent UNITED STATES PATENTS 2,273,468

